Malleable steel, the tang may be straightened or bent cold. X-ray inspected for internal flaws. The short .500" thread depth allows a very strong thread engagement when seated to the inside shoulder. It requires flash hole liner for flint use, or a powder drum for percussion use, each sold separately. The powder chamber is .285" diameter, to permit this plug to be used on rifles as small as .32 caliber. Enlarge it if desired, to facilitate cleaning. But the powder chamber must be smaller than the bore diameter, to avoid trapping a cleaning jag and patch. This plug lengthens the barrel assembly by nearly one inch.

Now made in several sizes and threads: * 7/8" octagon for use on 13/16 & 7/8" octagon barrels with 5/8-18 threads. * 1" octagon for use on 15/16 & 1" octagon barrels with 5/8-18 or 3/4-16 threads. * 1-1/8" for use on large 1-1/8" octagon barrels with 3/4-16 or 7/8-14 threads.